Right now anything that wants to fly must have a flight dynamics model implemented in JSBSim, which may not be viable for something like this. It will be possible to implement a custom physics later, that should work by generating whatever forces you want there to get that thing moving. Or even to position and rotate the object in a custom way, although that would make it harder to interact with collisions.
Anyway, without a usable flight dynamics model the movement may feel fake. Needs something like a generic auto-stabilizing thruster or anti-gravity based physics model. Or something.